The subject matter of this application is directed to video stabilization and, particularly, to detections of whether camera motion is intentional or unintentional and setting video stabilization parameters based on such detections.
Today, many portable electronic devices are equipped with digital cameras that are capable of capturing video. Captured video from these portable electronic devices may contain shake due to unintentional motion of the camera. Unintentional motion of the camera often occurs due to motion introduced by a shaking hand. To correct for the shake, the sequence of frames in the video may be adjusted by a video stabilization procedure. Video stabilization procedures can compensate for the undesired motion of the camera by different image processing techniques.
For example, video stabilization can be achieved by capturing a larger image than an image being displayed or recorded, thereby creating a spatial buffer of pixels around the edge of the recorded or displayed image. A crop region may be defined and positioned on a per frame basis to compensate for the detected motion. The pixels in the buffer can be used to provide the extra pixels needed to shift the crop region. Additional geometric transforms may be applied to the image inside the crop region to compensate for the effects of perspective.
The motion of portable electronic device can be detected by analyzing the content of frames or obtained from motion data provided by a motion sensor, such as a gyroscope, disposed within the portable electronic device. However, not all of the detected motion of the portable electronic device is unintentional. Intentional camera motion may be detected due to panning the camera or walking with the camera. If the above-discussed stabilization methods are applied to correct for intentional camera motion, undesired image processing may be performed on the captured image sequence. In addition, because intentional camera motion due to panning or walking may exceed the degree of image motion that the stabilization methods can correct, undesired periodic shifting of the image frame may be generated when the degree of motion exceeds the capabilities of the stabilization procedures.
Accordingly, the inventors have identified a need in the art for video stabilization that takes into account whether the motion of a portable device is intentional or unintentional. In particular, the inventors have identified a need in the art for video stabilization that adjusts the degree of video stabilization based on whether the motion of a portable device is intentional or unintentional and the classification of the intentional movement into various classes such as panning or holding steady.